一种输出可调CMOS带隙基准电压源的设计

传统设计中平衡温度时的带隙基准电压值是与工艺相关联的定值.主要基于通用的带隙技术讨论在CMOS工艺中基准产生的设计,在对基准产生原理与传统电路结构分析的基础上,设计出一种高PSRR输出可调带隙基准电压源.电路综合温度补偿、电流反馈和电阻分压技术,采用CSMC 0.5 tim CMOS混合信号工艺实现,并用Cadence的Spectre进行了仿真优化.仿真结果表明,带隙基准电压源在-15～80℃范围内输出为603.5 mV时的温度系数为6.84 × 10-6/℃,在1.8～5 V电路均可正常工作.流片后的测试结果验证了该方法的可行性,基准电压中心值可宽范围调整,各项性能参数满足设计要求.     

一种基于横向PNP管的低失调CMOS带隙基准源

基于横向寄生PNP管,提出了一种新颖结构的低失调CMOS带隙基准源。该带隙能够降低运放失调电压和镜像电流对基准电压的影响,提高带隙抗工艺失调的能力。仿真结果表明,基准电压为1.228 0V,在-40℃~125℃,典型偏差小于2.7mV,温度系数为13.9ppm/℃。该带隙具有较好的工艺稳定性,在各工艺角情况下,失调电压小于±25.3mV,比传统带隙相对精度提高了3.3倍。最后,基于0.35μm CMOS工艺实现了该电压基准源。     

高精度、低温度系数带隙基准电压源的设计与实现

为了提高传统带隙基准电压源的温度特性,本文采用一种双差分输入对的运算放大器对传统带隙基准电路进行高阶温度补偿。电路采用TSMC 0.35m CMOS混合信号工艺实现,采用Cadence公司Spectre软件进行电路仿真。仿真结果表明,带隙基准电压源在-40～125℃范围内的温度系数为2.2ppm/℃。     

带2阶补偿的CMOS带隙基准电压源

基于CSMC 0.5μm CMOS工艺,设计了一种具有低温度系数、带2阶补偿的带隙基准电压源.在传统放大器反馈结构带隙基准源的基础上,利用MOS器件的“饱和电流与过驱动电压成平方关系”产生2阶补偿量,对传统的带隙基准进行高阶补偿.具有电路实现简单,容易添加到传统带隙基准电路的优点.仿真结果表明,设计的基准电压源在5V电源电压下功耗为860 μW,最低工作电压为1.24 V,在-50℃～125℃的温度范围内获得了1.42×10-5/℃的温度系数,低频时的电源抑制比达到-86.3 dB.     

一种新型CMOS带隙基准电压源

传统带隙基准源电路采用PNP型三极管来产生ΔVbe,此结构使运放输入失调电压直接影响输出电压的精度。文章在对传统CMOS带隙电压基准源电路原理的分析基础上,提出了一种综合了一阶温度补偿和双极型带隙基准电路结构优点的高性能带隙基准电压源。采用NPN型三极管产生ΔVbe,消除了运放失调电压影响。该电路结构简洁,电源抑制比高。整个电路采用SMIC 0.18μmCMOS工艺实现。通过Cadence模拟软件进行仿真,带隙基准的输出电压为1.24V,在-40℃~120℃温度范围内其温度系数为30×10-6/℃,电源抑制比(PSRR)为-88 dB,电压拉偏特性为31.2×10-6/V。     

一种简单的高精度3阶补偿带隙电压基准源

基于普通带隙基准原理,设计了一种简单的3阶补偿带隙基准电路.这种补偿方式无需改变普通带隙基准的结构,仅增加很少的器件就能实现3阶补偿,具有电路实现简单、功耗低、容易嵌入传统带隙基准等优点.设计采用0.5 μm BiCMOS工艺,仿真结果表明,在-40℃～120℃温度范围内,5V工作电压下,该带隙基准源的输出电压为1.204 V,温度系数为1.9×10-6 V/℃,在1 kHz时,电源抑制比为58 dB.     

一个新型CMOS电流模带隙基准源

介绍了一个新型电流模带隙基准源,该带隙基准源的输出基准可以设计为任意大于硅材料的带隙电压（1.25V）的电压,避免在应用中使用运算放大器进行基准电压放大. 同时该结构消除了传统电流模带隙基准源的系统失调. 该带隙基准源已通过UMC 0.18μm混合信号工艺验证. 在1.6V电源电压下,该带隙基准源输出145V的基准电压,同时消耗27μA的电流. 在不采用曲率补偿的情况下,输出基准的温度系数在30℃ 到150℃的温度范围内可以达到23ppm/℃. 在电源电压从1.6变化到3V的情况下,带隙基准源的输入电压调整率为2.1mV/V. 该带隙基准源在低频（10Hz）的电源电压抑制比为40dB. 芯片面积（不包括Pads）为0.088mm2.     

一个新型CMOS电流模带隙基准源

介绍了一个新型电流模带隙基准源,该带隙基准源的输出基准可以设计为任意大于硅材料的带隙电压(1.25V)的电压,避免在应用中使用运算放大器进行基准电压放大.同时该结构消除了传统电流模带隙基准源的系统失调.该带隙基准源已通过UMC 0.18μm混合信号工艺验证.在1.6V电源电压下,该带隙基准源输出1.45V的基准电压,同时消耗27μA的电流.在不采用曲率补偿的情况下,输出基准的温度系数在30℃到150℃的温度范围内可以达到23ppm/℃.在电源电压从1.6变化到3V的情况下,带隙基准源的输入电压调整率为2.1mV/V.该带隙基准源在低频(10Hz)的电源电压抑制比为40dB.芯片面积(不包括Pads)为0.088mm2.     

一种高精度带隙基准电压源电路设计

针对传统CMOS带隙电压基准源电路电源电压较高,基准电压输出范围有限等问题,通过增加启动电路,并采用共源共栅结构的PTAT电流产生电路,设计了一种高精度、低温漂、与电源无关的具有稳定电压输出特性的带隙电压源.基于0.5μm高压BiCMOS工艺对电路进行了仿真,结果表明,在-40℃～85℃范围内,该带隙基准电路的温度系数为7ppm/℃,室温下的带隙基准电压为1.215 V.     

基于温度补偿的无运放低压带隙基准源设计

设计了一种带温度补偿的无运放低压带隙基准电路。提出了同时产生带隙基准电压源和基准电流源的技术,通过改进带隙基准电路中的带隙负载结构以及基准核心电路,基准电压和基准电流可以分别进行温度补偿。在0.5μmCMOS N阱工艺条件下,采用spectre进行模拟验证。仿真结果表明,在3.3V条件下,在-20～100℃范围内,带隙基准电压源和基准电流源的温度系数分别为35.6ppm/℃和37.8ppm/℃,直流时的电源抑制比为-68dB,基准源电路的供电电压范围为2.2～4.5V。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.